1. Technical Field
The present disclosure relates to surgical instruments. More particularly, the present disclosure relates to extramedullary alignment devices for the alignment of cut guides used in knee arthroplasty.
2. Description of the Related Art
Orthopaedic prostheses are commonly utilized to repair and/or replace damaged bone and tissue in the human body. For example, knee arthroplasty procedures are used to implant a knee prosthesis including a femoral component, which may replace the articular surface of one or both of the natural femoral condyles and/or the natural femoral sulcus. The knee prosthesis may also include a tibial component which replaces the articular surface of the proximal end of the tibia with one or more components adapted to articulate with the femoral component.
Prior to installation of femoral or tibial components, the damaged and/or diseased portion of the natural tibia and/or femur is typically resected. These resections leave resected tibial and/or femoral surfaces, which then receive the prosthetic tibial and/or femoral components. The prosthetic components are typically designed to have particular geometrical arrangements relative to the surrounding anatomical structures, such as bones and ligaments, as well as to one another and any other prosthetic structures utilized in the surgery. To achieve a desired geometrical arrangement of a given prosthesis, the resected surface of the bone to which the prosthesis is mounted is typically subject to geometrical constraints of its own.
Substantial design efforts have focused on providing cut guides which aid in producing a particular resected surface adapted to receive a particular implant or set of implants. In addition, design efforts have focused on providing intraoperative flexibility to the surgeon performing the implantation procedure, to aid the surgeon in making adjustments or modifications to the surgical procedure according to his or her judgment, and in view of the unique circumstances in each individual case.
For resection of the tibia in knee arthroplasty, a cut guide is typically used to remove the proximal articular surface of the natural tibia in preparation for implantation of a prosthetic tibial component adapted to articulate with either the natural femur or a prosthetic femoral component. Such tibial cut guides are typically placed in a fixed position relative to the tibia using either an “extramedullary” cut guide fixation system or, alternatively, an “intramedullary” cut guide fixation system.
Intramedullary cut guide alignment instruments generally include a portion extending into the medullary canal of the tibia, with a cut guide coupled to the intramedullary portion and, thus, indexed to the proximal tibia.
Extramedullary fixation systems, on the other hand, are disposed outside the medullary canal of the tibia, and may be indexed to the patient's ankle at one end and to the proximal tibia surface at the other end. Components of one exemplary extramedullary cut guide alignment system are shown in U.S. Design patent application No. 29/362,749, now issued as U.S. Pat. No. D646,395, filed May 28, 2010 and entitled “ANKLE CLAMP,” U.S. Design patent application No. 29/362,750, now issued as U.S. Pat. No. D651,313, filed May 28, 2010 and entitled “EXTRAMEDULLARY TELESCOPING TUBE AND ROD,” U.S. Design patent application No. 29/362,752, now issued as U.S. Pat. No. D651,314, filed May 28, 2010 and entitled “EXTRAMEDULLARY MODULAR SPIKE ARM AND POST,” and U.S. Design patent application No. 29/362,753, now issued as U.S. Pat. No. D646,388, filed May 28, 2010 and entitled “EXTRAMEDULLARY ROD ALIGNMENT ADAPTER,” each of which is commonly assigned with the present application, the entire disclosures of which are hereby expressly incorporated by reference herein.